


science guys being dudes

by reset-after-reset (relvius)



Category: Undertale (Video Game)
Genre: Bondage, M/M, Machines, Multiple Orgasms, No Genitals, Plot What Plot/Porn Without Plot, still-alive Gaster
Language: English
Status: Completed
Published: 2015-11-16
Updated: 2015-11-16
Packaged: 2018-05-01 21:21:06
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,077
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/5221217
Author URL: https://archiveofourown.org/users/relvius/pseuds/reset-after-reset
Summary: <blockquote class="userstuff">
              <p>i am not very good at names.<br/>Gaster has Sans on a machine. what more do you want? ¯\_(ツ)_/¯</p>
            </blockquote>





	science guys being dudes

Gaster’s hands work quickly and precisely as he loops another band through Sans’ pelvis. “The obturator foramen,” he says, grinning as he draws a finger around the inside of the hole. “Sensitive, huh?” Sans shudders. He wants to just say hell to this game, grab Gaster and hold him close and beg for his hands. But his own hands are tied -- literally, tied over his head by a rope hanging from the ceiling. He does his best to lean his hips into the touch, but is met by a sharp flick that makes him yelp. “I told you, no moving.”

“gaster,” Sans whines.

Gaster only smiles as he moves to the other hole, again tying Sans down. When Gaster dances his fingers across Sans’ hips a second time, Sans doesn't move. “Good.”

That was the last thing that needed tying. Now, his hips are tied in several places to the curved metal surface he sits on. A mound fills the bottom of his pelvis, while the rest of the seat is curved particularly for him,  like a saddle. His legs rest at his sides, also tied. Sans swears he could get off just by grinding against the cool metal and straps, but that would ruin the fun. It only took a day to make something as simple as this machine, but Sans has been immensely anxious to try it out ever since Gaster put forward the possibility.

Gaster, however, is less in a hurry. He stands back, admiring his handiwork -- or maybe, observing his subject. He's still dressed in his lab coat. Sans is painfully aware of how Gaster idly fidgets with the machine’s dial in one hand.

“gaster,” Sans repeats, then gives a short pathetic laugh. “i'm freezing here.” Or maybe it's the need in his chest making him quake. Gaster steps close again, now caressing down his sternum. Sans lets out a huff of frustration. “gast--”

He's cut off by the machine turning on. It vibrates every inch of his pelvis. It's so mild, a quiet hum resonating through the metal and straps, but it lights up every part of him as he realizes just what he’s gotten himself into.

“Good?” Gaster signs it this time, grinning too brightly.

Sans nods, although he's quickly frustrated by his inability to thrust too effectively into the sensations. “c’mon, more -- why do we even have such a low level, anyway?”

“Patience, Sans,” Gaster says. He's back giving attention to Sans’ chest, trailing fingers through the curve of every rib. It's just enough and not enough to be satisfying; Sans groans helplessly.

Eons later, Gaster reaches the bottommost ribs and finally steps the vibration up a notch. Sans lets out a breathy laugh at how good it feels. The dips of the metal fit him perfectly, the vibrations through him more exciting than he could have dreamed. He wants to stay like this forever, but at the same time realizes how close he already is to coming.

Gaster must be able to tell too. “Really, Sans?” he asks. “Already?”

Sans opens his mouth to try to explain how fucking good this feels, but all that escapes is a surprised moan as the metal’s hums increase again, now more than ever. He pulls down on his arms in vain, just wanting to buck and ride against the machine. He can’t keep himself from coming moments later, hard, as he tries to grind down into the metal, as if that would pull those overwhelming vibrations even further into his body.

The last wave of orgasm finally rolls over him, and soon he’s straining against the binds not to grind into the metal, but to try to pull himself away -- it’s too much, all at once. The machine continues humming and Gaster hasn’t stopped beaming. He places a single finger on the front of Sans’ pelvis, and even that makes Sans jump. “We’ve only just started, you know.” A light press down puts a new section of bone in direct contact with the metal, and Sans swears. Gaster’s other hand moves up and down Sans’ thigh, even the softest touches leaving stinging afterimages of touch.

“w-wait,” Sans stammers. “just--just let me rest. i--oh god.” Gaster’s finger begins to softly rub into Sans, and whatever he was trying to say stops mattering. He closes his eyes and lets his weight press him into the reverberations as the sensitivity of his bones melts into even greater pleasure.  “oh g-g-god--”

A moment of embarrassment crosses his mind as he realizes how loud he’s being. However, he can only quiet himself for a few seconds before Gaster spikes the machine’s intensity, making him practically yelp. Even when Gaster brings the level back to a more bearable level, Sans is still moaning deeply. A second orgasm hits him almost by surprise, and he’s shaking uncontrollably all over.

And it doesn’t stop. Sans can’t stop squirming, but any attempt to lift one part of his sensitive hips away from the machine just sends vibrations through another part of him. He’s begging now, not knowing if he’s even coherent but the “please”s and “gaster”s just pour out of his mouth uncontrollably. When he opens his eyes, he just sees Gaster just smiling away.

He can’t tell how long he lasts, but eventually, the squirming saps all the energy from his bones, and all he can do is let the bonds around his wrists carry his entire weight. Waves of pleasure continue to pound through him -- another orgasm? He couldn’t be sure anymore -- and the sudden fear crosses his mind that Gaster won’t let him go. It would take all the energy in him to wrest control of his voice, to form his mouth around their safe word. Fortunately, the machine begins to hum to a stop, although Sans swears he can still feel the reverberations through him.

Gaster gives him a quick carress on the cheekbone before working to untie Sans’ hips. Even just that is still too much touch; Sans lets out a small groan. When Sans’ hands are untied, he slumps forward, all but collapsing into Gaster’s chest. Gaster chuckles and asks, “Are you okay?”

Sans just nods. His shoulders are tingling and almost numb, but he’ll worry about the inevitable soreness later. Gaster carefully lifts him off of the machine and, looping an arm under Sans’ knees, picks him up. Sans practically melts into Gaster, mumbling, “i love you.”

Gaster hums contentedly.

 


End file.
